-LRB- CNN -RRB- -- World number one Caroline Wozniacki suffered another morale-sapping defeat at the French Open as she was dumped out by 28th seed Daniela Hantuchova .

The Dane , who is yet to win a Grand Slam tournament , was beaten 6-1 6-3 in just 73 minutes to extend her miserable run at Roland Garros .

Her best performance in Paris was reaching the quarterfinals in 2009 and she struggled against Hantuchova , from Slovakia , who was competing in her 41st major .

Hantuchova reeled off nine straight games to seal the opening set and take a commanding lead in the second but Woznaicki offered herself hope when she secured her first break to reduce the deficit to 4-2 .

But Hantuchova held serve twice to seal one of the biggest victories of her career and set up a meeting with 2009 champion Svetlana Kuznetsova in the last 16 , after she beat Canadian Rebecca Marino 6-0 6-4 .

`` She played very well today , better than me for sure , '' Wozniacki told a press conference . `` She knew what she wanted to do and I need to get back on the court and practice and come back stronger .

`` Kim had a tough loss yesterday and I had a tough loss today and that 's what can happen . Since we are number one and two we must be doing something right .

`` I am young and I get experience every time and you learn more from your losses than from your wins . ''

After Wozniacki 's exit , and Kim Clijsters defeat on Thursday , the trend for upsets continued as Australian 8th seed Samantha Stosur was beaten by unseeded Gisela Dulko .

The Argentine set the tone by taking the first four games of the match , and though she dropped the second set , Stosur 's 35 unforced errors counted as Dulko wrapped up the match .

Afterwards , she told a press conference she was dedicating her victory to her brother 's twins , Myla and Teo , who were born overnight .

`` Yesterday night I was awake really late , '' she said . `` You know , it was very emotional , because I would have loved to be there , but I 'm here . The key to the match was to start well , to be aggressive from the start , ''

Stosur added : `` She seemed to be out ahead a little bit better and really kind of be the one dictating the points , which , for me , I 'm usually the one able to do that . ''

Elsewhere , defending champion and fifth seed , Francesca Schiavone , from Italy , had no such trouble making the fourth round after her Chinese opponent Shuai Peng retired hurt with the score at 6-3 1-2 .

Russian third seed Vera Zvonareva beat Anastasia Rodionova , from Austria , 6-2 6-3 and Anastasia Pavlyuchenkova , the 14th seed , triumphed over Nuria Llagostera Vives , from Spain , 3-6 6-3 6-3 .

Serb Jelena Jankovic , the 10th seed , beat Bethanie Mattek-Sands , from the United States , 6-2 6-2 , while 11th seed Marion Bartoli , from France , beat Julia Goerges , from Germany , 3-6 6-2 6-4 .

@highlight

Caroline Wozniacki beaten at the French Open by Daniela Hantuchova

@highlight

World number one loses 6-1 6-3 in just 73 minutes at Roland Garros

@highlight

Australian 8th seed Samantha Stosur dumped out by Gisela Dulko

@highlight

Defending champion Francesca Schiavone through as Shuai Peng retires hurt